Control method and control apparatus of wind power generator set

ABSTRACT

A control method and a control apparatus of a wind power generator set are provided, in which a wind speed at a location of the wind power generator set is acquired, turbulence intensity is calculated according to the wind speed, and a wind speed distribution range corresponding to the turbulence intensity is determined; a thrust variation amplitude of the thrust in the wind speed distribution range is determined based on a relationship among the thrust suffered by a wind wheel of the wind power generator set, a thrust coefficient and the wind speed; and a maximum rotating speed and a maximum torque of the wind wheel in the wind speed distribution range are adjusted according to the thrust variation amplitude. The maximum rotating speed and the maximum torque makes a fatigue load of the wind power generator set in the wind speed distribution range meet a preset standard.

The present application claims the priority to Chinese PatentApplication No. 201510848517.0, titled “CONTROL METHOD AND CONTROLAPPARATUS OF WIND POWER GENERATOR SET” and filed with the StateIntellectual Property Office of the People's Republic of China on Nov.27, 2015, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present disclosure relates to the technical field of wind powergenerator set control, and in particular to a control method and acontrol apparatus of a wind power generator set.

BACKGROUND OF THE INVENTION

Wind energy is a kind of clean and safe renewable resources. Wind powergeneration by means of a wind power generator set can guarantee energysecurity, adjust energy structure and alleviate environmental pollution,and thus is one of the most mature, the most widely used and the bestprospective power generation methods, which has a great significance toachieve sustainable development.

A wind power generator set is usually designed by taking a level of windresource characteristics specified in the IEC standards or GLspecifications as an input standard. Turbulence in the wind resourcecharacteristics has a direct impact on a fatigue load of the wind powergenerator set and is directly relevant to extreme gusts giving rise toan extreme load, thus having a great influence on lifespan of the windpower generator set. The turbulence is a natural uncontrollable factor,but turbulence intensity can be measured. To reduce influence of theturbulence on the wind power generator set, generally actual measuredturbulence intensity is compared with the levels of turbulence intensityspecified in the IEC standards or GL specifications. When the actualmeasured turbulence intensity is beyond a specified level, somecorresponding measures are taken to guarantee the wind power generatorset in stable and safe operation. In the prior art, the influence of theturbulence beyond the specified level on the wind power generator set isreduced by means of a shutdown when the actual measured turbulenceintensity is beyond the specified level.

However, the shutdown manner in the prior art results in a serious lossof generated electric energy. The loss has little influence on a windpower plant with a flat terrain, an outstanding wind powercharacteristic, and with a small scale of wind power generator set notat a prevailing wind direction, while has great influence on a windpower plant with a complex terrain, a less obvious wind powercharacteristic, and with a large scale of wind power generator set or ata prevailing wind direction.

SUMMARY OF THE INVENTION

In view of the above, the present disclosure provides a control methodand an apparatus of a wind power generator set, to not only reduceinfluence on a wind power generator set when turbulence intensity isbeyond the specified level but also lower a loss of generated electricenergy.

In order to attain the foregoing objective, the present disclosureprovides the following technical solutions.

In an aspect, there is provided a control method of a wind powergenerator set in the present disclosure. The method includes:

acquiring a wind speed at a location of the wind power generator set,calculating turbulence intensity according to the wind speed, anddetermining a wind speed distribution range corresponding to theturbulence intensity;

determining a thrust variation amplitude of thrust in the wind speeddistribution range based on a relationship among the thrust suffered bya wind wheel of the wind power generator set, a thrust coefficient andthe wind speed; and

adjusting a maximum rotating speed and a maximum torque of the windwheel in the wind speed distribution range according to the thrustvariation amplitude, where the maximum rotating speed and the maximumtorque makes a fatigue load of the wind power generator set in the windspeed distribution range meet a preset standard.

Preferably, the above step of acquiring a wind speed at a location ofthe wind power generator set, calculating turbulence intensity accordingto the wind speed, and determining a wind speed distribution rangecorresponding to the turbulence intensity includes:

acquiring a wind speed at the location of the wind power generator setin a preset period, and calculating an average wind speed v in thepreset period;

calculating the turbulence intensity

$I = {\frac{\delta}{\overset{\_}{v}} = \frac{\sqrt{\frac{1}{N}{\sum_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}}{\overset{\_}{v}}}$

according to the average wind speed v, and determining a Gaussiandistribution

${{f(v)} = {\frac{1}{\delta \sqrt{2\pi}}e^{- \frac{{({v - \overset{\_}{v}})}^{2}}{2\delta^{2}}}}},$

with a center of v and a standard deviation of

${\delta = \sqrt{\frac{1}{N}{\sum_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}},$

of a wind speed distribution range corresponding to the turbulenceintensity according to the turbulence intensity

${I = {\frac{\delta}{\overset{\_}{v}} = \frac{\sqrt{\frac{1}{N}{\sum_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}}{\overset{\_}{v}}}};$

and

determining the wind speed distribution range (v−1.96δ, v+1.96δ)according to the theory of small probability event and the Gaussiandistributior

${{f(v)} = {\frac{1}{\delta \sqrt{2\pi}}e^{- \frac{{({v - \overset{\_}{v}})}^{2}}{2\delta^{2}}}}},$

where I denotes the turbulence intensity corresponding to the averagewind speed v, v_(i) denotes an instantaneous wind speed of the i-thsampling point, and N denotes the number of sampling points in thepreset period.

Preferably, the above step of determining a thrust variation amplitudeof thrust in the wind speed distribution range based on a relationshipamong the thrust suffered by a wind wheel of the wind power generatorset, a thrust coefficient and the wind speed includes:

determining a relation

$F = {\frac{1}{2}\rho \; {Av}^{2}{C_{t}\left( {\beta,\frac{\omega \; R}{v}} \right)}}$

among the thrust, a pitch angle β of a blade of a wind wheel and a windwheel rotating speed ω according to a relation F=1/2ρAv²C_(t)(β, λ)among the thrust suffered by the wind wheel of the wind power generatorset, the thrust coefficient and the wind speed and according to a tipspeed ratio

$\lambda = \frac{\omega \; R}{v}$

of the wind wheel;

determining a minimum thrust

$F_{\min - I} = {\frac{1}{2}\rho \; {Av}_{\min}^{2}{C_{t}\left( {\beta_{opt},\frac{\omega_{low}R}{v_{\min}}} \right)}}$

corresponding to a minimum wind speed v_(min)=v−1.96δ in the wind speeddistribution range and a maximum thrust

$F_{\max - I} = {\frac{1}{2}\rho \; {Av}_{\max}^{2}{C_{t}\left( {\beta_{opt},\frac{\omega_{high}R}{v_{\max}}} \right)}}$

corresponding to a maximum wind speed v_(max)=v+1.96δ in the wind speeddistribution range according to the formula

${F = {\frac{1}{2}\rho \; {Av}^{2}{C_{t}\left( {\beta,\frac{\omega \; R}{v}} \right)}}};$

and

determining a thrust variation amplitude

$F_{I} = \frac{\sqrt{\frac{\left( {\left( {F_{\max - I} - F_{\overset{\_}{v}}} \right)^{2} + \left( {F_{\min - I} - F_{\overset{\_}{v}}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}}$

of the thrust in the wind speed distribution range according to theminimum thrust, the maximum thrust and a relation between the thrust andthe wind speed

${F = \frac{\sqrt{\frac{1}{N}{\sum_{i = 1}^{N}\left( {F_{v_{i}} - F_{\overset{\_}{v}}} \right)^{2}}}}{F_{\overset{\_}{v}}}},$

where ρ is an air density, A is a wind wheel swept area, v is a windspeed, C_(t)(β, λ) is the thrust coefficient relevant to the pitch angleβ of the blade of the wind wheel and the tip speed ratio λ, R is a windwheel radius, ω_(min) is a minimum rotating speed of the wind powergenerator set in grid connection, ω_(low) is a minimum rotating speed ofthe wind power generator set, ω_(high) is a maximum rotating speed ofthe wind power generator set, β_(opt) is an optimum pitch angle, F _(v), is thrust suffered at the average wind speed v, F_(I) is a thrustvariation amplitude during the preset time at the average wind speed vand at the turbulence intensity I, and F_(v) _(i) is thrust suffered bythe wind wheel at the i-th sampling point with an instantaneous windspeed of v_(i).

Preferably, the above step of adjusting a maximum rotating speed and amaximum torque of the wind wheel in the wind speed distribution rangeaccording to the thrust variation amplitude includes:

adjusting the maximum rotating speed ω_(high) of the wind powergenerator set in the wind speed distribution range according to

$F_{I_{2}} = {\frac{\sqrt{\frac{\left( {\left( {F_{\max - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2} + \left( {F_{\min - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}^{\prime}} = {\frac{\sqrt{\frac{\left( {\left( {F_{\max - I_{1}} - F_{\overset{\_}{v}}} \right)^{2} + \left( {F_{\min - I_{2}} - F_{\overset{\_}{v}}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}} = F_{I_{1}}}}$

when the turbulence intensity increases from I₁ to I₂ and the thrustvariation amplitude changes from (F_(min-I) ₁ , F_(max-I) ₁ ) to(F_(min-I) ₂ , F_(max-I) ₂ ) due to variation of the wind speed; and

adjusting a maximum torque T_(max-I) ₂ =T_(max-I) ₁ −T_(min-I) ₁+T_(min-I) ₂ of the wind power generator set in the wind speeddistribution range according to T_(I) ₁ =T_(max-I) ₁ −T_(min-I) ₁=T_(max-I) ₂ −T_(min-I) ₂ =T_(I) ₂ when the turbulence intensityincreases from I₁ to I₂ and the torque variation amplitude of the windpower generator set changes from (T_(min-I) ₁ , T_(max-I) ₁ ) to(T_(min-I) ₂ , T_(max-I) ₂ ) due to variation of the wind speed,

where F′ _(v) is thrust corresponding to the maximum rotating speed.

Preferably, the method further includes:

restricting the maximum torque according to a power generation systemcharacteristic curve of the wind power generator set.

In another aspect, there is provided a control apparatus of a wind powergenerator set in the present disclosure. The apparatus includes:

an acquisition module, configured to acquire a wind speed at a locationof the wind power generator set, calculating turbulence intensityaccording to the wind speed, and determining a wind speed distributionrange corresponding to the turbulence intensity;

a determining module, configured to determine a thrust variationamplitude of the thrust in the wind speed distribution range based on arelationship among the thrust suffered by a wind wheel of the wind powergenerator set, a thrust coefficient and the wind speed; and

an adjusting module, configured to adjust a maximum rotating speed and amaximum torque of the wind wheel in the wind speed distribution rangeaccording to the thrust variation amplitude, and the maximum rotatingspeed and the maximum torque makes a fatigue load of the wind powergenerator set in the wind speed distribution range meet a presetstandard.

Preferably, the acquisition module includes:

an acquisition module, configured to acquire a wind speed at thelocation of the wind power generator set in a preset period, andcalculating an average wind speed v in the preset period;

a calculation unit, configured to calculate turbulence intensity

$I = {\frac{\delta}{\overset{\_}{v}} = \frac{\sqrt{\frac{1}{N}{\sum_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}}{\overset{\_}{v}}}$

according to the average wind speed v, and determining a Gaussiandistribution

${{f(v)} = {\frac{1}{\delta \sqrt{2\pi}}e^{- \frac{{({v - \overset{\_}{v}})}^{2}}{2\delta^{2}}}}},$

with a center of v and a standard deviation of

$\sqrt{\frac{1}{N}{\sum_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}},$

of a wind speed distribution range corresponding to the turbulenceintensity according to the turbulence intensity

${I = {\frac{\delta}{\overset{\_}{v}} = \frac{\sqrt{\frac{1}{N}{\sum_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}}{\overset{\_}{v}}}};$

and

a first determining unit, configured to determine the wind speeddistribution range (v−1.96δ, v+1.96δ) according to the theory of smallprobability event and the Gaussian distribution

${f(v)} = {\frac{1}{\delta \; \sqrt{2\; \pi}}e^{{- \frac{{({v - \overset{\_}{v}})}^{2}}{2\; \delta^{2}}};}}$

where I denotes the turbulence intensity corresponding to the averagewind speed v, v_(i) denotes an instantaneous wind speed of the i-thsampling point, and N denotes the number of sampling points in thepreset period.

Preferably, the determining module includes:

a second determining unit, configured to determine a relation

$F = {\frac{1}{2}\rho \; {Av}^{2}{C_{t}\left( {\beta,\frac{\omega \; R}{v}} \right)}}$

among the thrust, a pitch angle β of a blade of a wind wheel and a windwheel rotating speed ω according to a relation F=1/2ρAv²C_(t)(β, λ)among the thrust suffered by the wind wheel of the wind power generatorset, a thrust coefficient and the wind speed and according to a tipspeed ratio

$\lambda = \frac{\omega \; R}{v}$

of the wind wheel;

a third determining unit, configured to determine a minimum thrust

$F_{\min - I} = {\frac{1}{2}\rho \; {Av}_{\min}^{2}{C_{t}\left( {\beta_{opt},\frac{{\omega_{low}R}\;}{v_{\min}}} \right)}}$

corresponding to a minimum wind speed v_(min)=v−1.96δ in the wind speeddistribution range and a maximum thrust

$F_{\max - I} = {\frac{1}{2}\rho \; {Av}_{\max}^{2}{C_{t}\left( {\beta_{opt},\frac{{\omega_{high}R}\;}{v_{\max}}} \right)}}$

corresponding to a maximum wind speed v_(max)=v+1.96δ in the wind speeddistribution range according to the formula

${F = {\frac{1}{2}\rho \; {Av}^{2}{C_{t}\left( {\beta,\frac{{\omega \; R}\;}{v}} \right)}}};$

and

a fourth determining unit, configured to determine a thrust variationamplitude

$F_{I} = \frac{\sqrt{\frac{\left( {\left( {F_{\max - I} - F_{\overset{\_}{v}}} \right)^{2} + \left( {F_{\min - I} - F_{\overset{\_}{v}}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}}$

of the thrust in the wind speed distribution range according to theminimum thrust, the maximum thrust and a relation between the thrust andthe wind speed

${F = \frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\; \left( {F_{v_{i}} - F_{\overset{\_}{v}}} \right)^{2}}}}{F_{\overset{\_}{v}}}};$

where ρ is an air density, A is a wind wheel swept area, v is a windspeed, C_(t)(β, λ) is the thrust coefficient relevant to the pitch angleβ of the blade of the wind wheel and the tip speed ratio λ, R is a windwheel radius, ω_(min) is a minimum rotating speed of the wind powergenerator set in grid connection, ω_(low) is a minimum rotating speed ofthe wind power generator set, ω_(high) is a maximum rotating speed ofthe wind power generator set, β_(opt) is an optimum pitch angle, F _(v), is thrust suffered at the average wind speed v, F_(I) is a thrustvariation amplitude during the preset time at the average wind speed vand at the turbulence intensity I, and F_(v) _(i) is thrust suffered bythe wind wheel at the i-th sampling point with an instantaneous windspeed of v_(i).

Preferably, the adjusting module includes:

a rotating speed adjusting unit, configured to adjust a maximum rotatingspeed ω_(high) of the wind power generator set in the wind speeddistribution range according to

$F_{I_{2}} = {\frac{\sqrt{\frac{\left( {\left( {F_{\max - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2} + \left( {F_{\min - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}^{\prime}} = {\frac{\sqrt{\frac{\left( {\left( {F_{\max - I_{1}} - F_{\overset{\_}{v}}} \right)^{2} + \left( {F_{\min - I_{1}} - F_{\overset{\_}{v}}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}} = F_{I_{1}}}}$

when the turbulence intensity increases from I₁ to I₂ and the thrustvariation amplitude changes from (F_(min-I) ₁ , F_(max-I) ₁ ) to(F_(min-I) ₂ , F_(max-I) ₂ ) due to variation of the wind speed; and

a torque adjusting unit, configured to adjust a maximum torque T_(max-I)₂ =T_(max-I) ₁ −T_(min-I) ₁ +T_(min-I) ₂ of the wind power generator setin the wind speed distribution range according to T_(I) ₁ =T_(max-I) ₁−T_(min-I) ₁ =T_(max-I) ₂ −T_(min-I) ₂ =T_(I) ₂ when the turbulenceintensity increases from I₁ to I₂ to I₂ and the torque variationamplitude of the wind power generator set changes from (T_(min-I) ₁ ,T_(max-I) ₁ ) to (T_(min-I) ₂ , T_(max-I) ₂ ) due to variation of thewind speed;

where F′ _(v) is thrust corresponding to the maximum rotating speed.

Preferably, the apparatus further includes:

a restricting module, configured to restrict the maximum torqueaccording to a power generation system characteristic curve of the windpower generator set.

It is apparent from the above technical solutions that, with the controlmethod and a control apparatus of a wind power generator set provided inthe present disclosure, a wind speed at a location of the wind powergenerator set is acquired, turbulence intensity is calculated accordingto the wind speed, and a wind speed distribution range corresponding tothe turbulence intensity is determined; a thrust variation amplitude ofthe thrust in the wind speed distribution range is determined based on arelationship among the thrust suffered by a wind wheel of the wind powergenerator set, a thrust coefficient and the wind speed; and a maximumrotating speed and a maximum torque of the wind wheel in the wind speeddistribution range are adjusted according to the thrust variationamplitude, where the maximum rotating speed and the maximum torque makesa fatigue load of the wind power generator set in the wind speeddistribution range meet a preset standard. With the technical solutionsprovided in the present disclosure, a wind speed distribution range isdetermined according to actual measured turbulence intensity, and then amaximum rotating speed and a maximum torque are adjusted according tothe wind speed distribution range. When the turbulence intensity isbeyond a specified level, a fatigue load of a wind power generator setin the wind speed distribution range is made to meet a preset standardby adjusting the maximum rotating speed and the maximum torque, insteadof shutting down the wind power generator set. Thereby influence on thewind power generator set is reduced when the turbulence intensity isbeyond the specified level and a loss of generated electric energy islowered.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompany drawings used in the description of the embodiments willbe described briefly as follows, so that the technical solutionsaccording to the embodiments of the present disclosure will become moreapparent. It is clear that the accompany drawings in the followingdescription are only some embodiments of the present disclosure. Forthose skilled in the art, other accompany drawings may be obtainedaccording to these accompany drawings without any creative work.

FIG. 1 is a schematic diagram illustrating a wind speed distributionrange corresponding to turbulence intensity;

FIG. 2 is a schematic diagram illustrating a wind speed distributionrange variation corresponding to turbulence intensity variation ;

FIG. 3 is a schematic diagram illustrating a relationship between a tipspeed ratio and a thrust coefficient provided in the present disclosure;

FIG. 4 is a schematic diagram illustrating control of a rotating speedand a torque of a wind power generator set provided in the presentdisclosure;

FIG. 5 is a schematic diagram illustrating an operation curve of arotating speed and a torque of a wind power generator set provided inthe present disclosure;

FIG. 6 is a flowchart of a control method of a wind power generator setprovided in the present disclosure;

FIG. 7 is a structural schematic diagram illustrating a controlapparatus of a wind power generator set provided in the presentdisclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The technical solutions according to the embodiments of the presentdisclosure will be described clearly and completely as follows inconjunction with the accompany drawings in the embodiments of thepresent disclosure. It is clear that the described embodiments are onlya part of the embodiments according to the present disclosure. All theother embodiments obtained by those skilled in the art based on theembodiments in the present disclosure without any creative work fallswithin the scope of the present disclosure.

FIG. 6 is a flowchart of a control method of a wind power generator setprovided in the present disclosure.

As shown in FIG. 6, a control method of a wind power generator setprovided according to an embodiment of the present disclosure includessteps S101 to S103.

In step S101, a wind speed at a location of the wind power generator setis acquired, turbulence intensity is calculated according to the windspeed, and a wind speed distribution range corresponding to theturbulence intensity is determined.

The turbulence intensity (TI) refers to random variation amplitude of awind speed in ten minutes, which is defined as a ratio of an averagewind speed standard deviation in ten minutes to the average wind speedduring the period. The turbulence intensity is a dominating factor of anormal fatigue load sustained by a wind power generator set duringoperation, and is also one of the most important parameters of safetylevel classification for a wind power generator set in IEC61400-1.

The relation between turbulence intensity and wind speed is expressed asformula (1):

$\begin{matrix}{I = {\frac{\delta}{\overset{\_}{v}} = \frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\; \left( {v_{i} - \overset{\_}{v}} \right)^{2}}}}{\overset{\_}{v}}}} & (1)\end{matrix}$

where v denotes an average wind speed in ten minutes, I denotes theturbulence intensity corresponding to the average wind speed v, δdenotes standard deviation, v_(i) denotes an instantaneous wind speed atthe i-th sampling point, and N denotes a sampling number in ten minutes.

According to the definition of turbulence intensity, a wind speeddistribution corresponding to the turbulence intensity can be understoodas a Gaussian distribution of the wind speed, with a center of v and astandard deviation of

$\delta = \sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\; {\left( {v_{1} - \overset{\_}{v}} \right)^{2}.}}}$

The wind speed distribution is formulated as formula (2):

$\begin{matrix}{{f(v)} = {\frac{1}{\delta \sqrt{2\; \pi}}e^{- \frac{{({v - \overset{\_}{v}})}^{2}}{2\; \delta^{2}}}}} & (2)\end{matrix}$

As shown in FIG. 1, a schematic diagram of wind speed distributioncorresponding to any known average wind speed and standard deviation canbe drawn according to formula (2). Combining with the theory of smallprobability events (probability of occurrence is small than 5%) in theprobability theory and an important area proportional relation in aGaussian distribution, i.e., the area within the horizontal axis range(v−1.96δ, v+1.96δ) is 95.4% of the total area, it can be considered thatthe wind speed is mainly distributed in the range of (v−1.96δ, v+1.96δ)due to the influence of turbulence intensity, which is illustrated witha thick line in FIG. 1.

When turbulence intensity corresponding to the same average wind speedincreases, the corresponding wind speed distribution range will beenlarged. As shown in FIG. 2, as the increase of turbulence intensity,the main wind speed distribution range extends from (v−1.96δ, v+1.96δ)to (v−1.96δ₁, v+1.96δ₁), that is, the maximum wind speed v_(max) in thewind speed distribution is increased from v−1.96δ, v+1.96δ to v−1.96δ,v+1.96δ₁.

From the foregoing, in embodiments of the present disclosure, the stepof acquiring a wind speed at a location of the wind power generator set,calculating turbulence intensity according to the wind speed, anddetermining a wind speed distribution range corresponding to theturbulence intensity includes:

acquiring a wind speed at the location of the wind power generator setin a preset period like ten minutes, and calculating an average windspeed v in the preset period;

calculating turbulence intensity

$I = {\frac{\delta}{\overset{\_}{v}} = \frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\; \left( {v_{1} - \overset{\_}{v}} \right)^{2}}}}{\overset{\_}{v}}}$

according to the average wind speed v, and determining a Gaussiandistribution

${{f(v)} = {\frac{1}{\delta \sqrt{2\; \pi}}e^{- \frac{{({v - \overset{\_}{v}})}^{2}}{2\; \delta^{2}}}}},$

with a center of v and a standard deviation of

$\delta = \sqrt{{\frac{1}{N}{\sum\limits_{i = 1}^{N}\; \left( {v_{i} - \overset{\_}{v}} \right)^{2}}},}$

of a wind speed distribution range corresponding to the turbulenceintensity according to the turbulence intensity

${I = {\frac{\delta}{\overset{\_}{v}} = \frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}}{\overset{\_}{v}}}};{and}$

and

determining the wind speed distribution range (v−1.96δ, v+1.96δ)according to the theory of small probability event and the Gaussiandistribution

${{f(v)} = {\frac{1}{\delta \sqrt{2\pi}}e^{- \frac{{({v - \overset{\_}{v}})}^{2}}{2\delta^{2}}}}},$

where I denotes the turbulence intensity corresponding to the averagewind speed v, v_(i) denotes an instantaneous wind speed of the i-thsampling point, and N denotes the number of sampling points in thepreset period.

In step S102, a thrust variation amplitude of the thrust in the windspeed distribution range is determined based on a relationship among thethrust suffered by a wind wheel of the wind power generator set, athrust coefficient and the wind speed.

In combination with a dominant load distribution of the wind powergenerator set, it is known that the turbulence near a rated wind speedplays a dominant role on a fatigue load of most key or importantcomponents of the wind power generator set. For any wind speed in a fullwind speed distribution range of a specific wind power generator set,the turbulence intensity beyond the specified level should be convertedinto a theoretical rated wind speed by a calculation method according tostandard turbulence intensity definition, and a control is performed todecrease the fatigue load generated by a over-standard turbulenceintensity corresponding to the rated wind speed.

According to the following relation (3) among thrust, a wind speed and athrust coefficient, the thrust suffered by a wind wheel is in directproportion to square of the wind speed and the thrust coefficient.Therefore, the thrust coefficient needs to be decreased to reduce thethrust when the wind speed increases.

F=1/2ρAv ² C _(t)(β, λ)   (3)

where ρ is an air density, A is a wind wheel swept area, v is a windspeed, and C_(t)(β, λ) is the thrust coefficient relevant to a pitchangle β of a blade and a tip speed ratio.

The tip speed ratio λ, is expressed as:

$\begin{matrix}{\lambda = \frac{\omega \; R}{v}} & (4)\end{matrix}$

where ω is a wind wheel rotating speed, R is a wind wheel radius, and vis the wind speed.

There is no direct transformational relation between the thrustcoefficient C_(t) and the pitch angle β. Moreover, it is complicated tobuild a relation between them due to the impact of a non-linearaerodynamic characteristic of the blade. Furthermore, if a minimum pitchangle is configured according to turbulence intensity, the ability ofabsorbing wind energy at a low wind speed may be decreased, resulting inan overmuch loss of the wind energy. However, since the thrustcoefficient is directly related to the tip speed ratio, and the tipspeed ratio is directly related to the rotating speed, a direct relationC_(t)=f(ω) between the thrust coefficient and the rotating speed in thecondition of a specific pitch angle β is built. As shown in FIG. 3, “o”represents a corresponding relation between a tip speed ratio of a bladeand a thrust coefficient, and the solid line is a fitting relation curveby the following second-order formula (5).

$\begin{matrix}{C_{t} = {{a \star \left( \frac{\omega \; R}{v} \right)^{2}} + {b \star \left( \frac{\omega \; R}{v} \right)} + c}} & (5)\end{matrix}$

By further combining with the tip speed ratio formula (4), it is knownthat the thrust coefficient is relevant to pitch angle of a blade andwind speed of a wind wheel. Therefore, by adjusting the pitch angle of ablade or the wind speed of a wind wheel, the purpose of decreasing thethrust coefficient may be realized.

A relation among the thrust, the pitch angle and the rotating speed of awind wheel is derived in follows according to formulas (3)-(4):

$\begin{matrix}{F = {\frac{1}{2}\rho \; {Av}^{2}{C_{t}\left( {\beta,\frac{\omega \; R}{v}} \right)}}} & (6)\end{matrix}$

Considering an extreme condition in combination with the influence ofturbulence intensity on the main wind speed distribution, it is knownfrom FIG. 4 that the wind wheel maintains at a rated rotating speed,i.e., ω_(high)=ω_(r), and maintains at an optimum pitch angle, i.e.,β=β_(opt), when the wind speed generated by the turbulence increasesfrom v to a maximum wind speed v_(max)=v+1.96δ, for a reason ofhysteresis of change of wind wheel rotating and pitch action. A maximumthrust produced for an increase of the wind speed is obtained in formula(7) by combining with formula (6).

$\begin{matrix}{F_{\max - I} = {\frac{1}{2}\rho \; {Av}_{\max}^{2}{C_{t}\left( {\beta_{opt},\frac{\omega_{high}R}{v_{\max}}} \right)}}} & (7)\end{matrix}$

When the wind speed generated by the turbulence decreases from v to aminimum wind speed v_(min)=1.96δ, it is known according to FIG. 4, thewind wheel rotating speed may fall in region II or region I forinfluence of wind speed range. When the rotating speed is in region I,the rotating speed is ω_(low)=ω_(min), where ω_(min) is a minimumrotating speed of a wind power generator set in grid connection. Whenthe rotating speed is in region II, the wind power generator set isrunning in a state with an optimum tip speed ratio, and thecorresponding rotating speed may be calculated by the following formula:

$\begin{matrix}{\omega_{low} = \frac{\lambda_{opt}v}{R}} & (8)\end{matrix}$

where λ_(opt) is an optimum tip speed ratio.

The minimum thrust is obtained in the following formula (9) by combiningwith formula (6).

$\begin{matrix}{F_{\min - 1} = {\frac{1}{2}\rho \; {Av}_{\min}^{2}{C_{t}\left( {\beta_{opt},\frac{\omega_{low}R}{v_{\min}}} \right)}}} & (9)\end{matrix}$

Combining with the definition of turbulence intensity, force variationintensity of a wind power generator set in a direction perpendicular tothe wind wheel plane is defined as formula (10), representing variationamplitude of the thrust suffered by the wind power generator setproduced by random wind speed variation, as the principle of theturbulence intensity definition.

$\begin{matrix}{F = \frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {F_{v_{i}} - F_{\overset{\_}{v}}} \right)^{2}}}}{F_{\overset{\_}{v}}}} & (10) \\{F_{\overset{\_}{v}} = {\frac{1}{2}\rho \; A{\overset{\_}{v}}^{2}{C_{t}\left( {\beta_{opt},\frac{\omega_{r}\; R}{\overset{\_}{v}}} \right)}}} & (11)\end{matrix}$

where F _(v) is thrust suffered at the average wind speed v, F_(I) is athrust variation amplitude during the preset time at the average windspeed v and at the turbulence intensity I, F_(v) _(i) is thrust sufferedby the wind wheel at the i-th sampling point with an instantaneous windspeed of v_(i) and N is the number of sampling points.

Considering an extreme condition and engineering simplification, F_(I)in different turbulence intensity is calculated by formula (12)according to formula (10).

$\begin{matrix}{F_{I} = \frac{\frac{\sqrt{\left( {\left( {F_{\max - I} - F_{\overset{\_}{v}}} \right)^{2} + \left( {F_{\min - I} - F_{\overset{\_}{v}}} \right)^{2}} \right)}}{2}}{F_{\overset{\_}{v}}}} & (12)\end{matrix}$

From the foregoing, in embodiments of the present disclosure, the stepof determining a thrust variation amplitude of the thrust in the windspeed distribution range based on a relationship among the thrustsuffered by a wind wheel of the wind power generator set, a thrustcoefficient and the wind speed includes:

determining a relation

$F = {\frac{1}{2}\rho \; {Av}^{2}{C_{t}\left( {\beta,\frac{\omega \; R}{v}} \right)}}$

among the thrust, a pitch angle β of a blade of a wind wheel and a windwheel rotating speed ω according to a relation F=1/2ρAv²C_(t)(β, λ)among the thrust suffered by the wind wheel of the wind power generatorset, a thrust coefficient and the wind speed, and according to a tipspeed ratio

$\lambda = \frac{\omega \; R}{v}$

of the wind wheel;

determining a minimum thrust

$F_{\min - I} = {\frac{1}{2}\rho \; {Av}_{\min}^{2}{C_{t}\left( {\beta_{opt},\frac{\omega_{low}R}{v_{\min}}} \right)}}$

corresponding to a minimum wind speed v_(min)=v1.96δ in the wind speeddistribution range and a maximum thrust

$F_{\max - I} = {\frac{1}{2}\rho \; {Av}_{\max}^{2}{C_{t}\left( {\beta_{opt},\frac{\omega_{high}R}{v_{\max}}} \right)}}$

corresponding to a maximum wind speed v_(max)=v+1.96δ in the wind speeddistribution range according to the formula

${F = {\frac{1}{2}\rho \; {Av}^{2}{C_{t}\left( {\beta,\frac{\omega \; R}{v}} \right)}}};$

and

determining a thrust variation amplitude

$F_{I} = \frac{\sqrt{\frac{\left( {\left( {F_{\max - I} - F_{\overset{\_}{v}}} \right)^{2} + \left( {F_{\min - I} - F_{\overset{\_}{v}}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}}$

of the thrust in the wind speed distribution range according to theminimum thrust, the maximum thrust and the relation between the thrustand the wind speed

$F = {\frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {F_{v_{i}} - F_{\overset{\_}{v}}} \right)^{2}}}}{F_{\overset{\_}{v}}}.}$

In the above, ρ is an air density, A is a wind wheel swept area, v is awind speed, C_(t)(β, λ) is the thrust coefficient relevant to the pitchangle β of the blade of the wind wheel and the tip speed ratio λ, R is awind wheel radius, ω_(min) is a minimum rotating speed of the wind powergenerator set in grid connection, ω_(low) is a minimum rotating speed ofthe wind power generator set, ω_(high) is a maximum rotating speed ofthe wind power generator set, β_(opt) is an optimum pitch angle, F _(v)is thrust suffered at the average wind speed v, F_(I) is a thrustvariation amplitude during the preset time at the average wind speed vand at the turbulence intensity I, and F_(v)is thrust suffered by thewind wheel at the i-th sampling point with an instantaneous wind speedof v_(i).

In step S103, a maximum rotating speed and a maximum torque of the windwheel in the wind speed distribution range are adjusted according to thethrust variation amplitude. The maximum rotating speed and the maximumtorque makes a fatigue load of the wind power generator set in the windspeed distribution range meet a preset standard.

According to the theory of rain flow counting and equivalent loadcalculation of a fatigue load, F_(I) needs to remain unchanged if thefatigue load of a wind power generator set keeps unchanged underdifferent turbulence intensity conditions. That is, when the turbulenceintensity increases from I₁ to I₂, it is necessary to keep F_(I) ₂=F_(I) ₁ . According to formula (6), when pitch angle remains unchanged,the force F can be changed only by adjusting the rotating speed ω.According to formula (8), a minimum rotating speed is difficult toadjust due to the influence of an optimum tip speed ratio and the windspeed, while the rotating speed ω_(high) is not influenced and thus canbe adjusted freely. So F_(I) is controlled by adjusting rated rotatingspeed ω_(r), and the corresponding F _(v) will be changed when adjustingthe ω_(r). Based on the above, ω′_(r) satisfying the equation (13) iscalculated in combination with formulas (5)-(12).

$\begin{matrix}{F_{I_{2}} = {\frac{\sqrt{\frac{\left( {\left( {F_{\max - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2} + \left( {F_{\min - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}^{\prime}} = {\frac{\sqrt{\frac{\left( {\left( {F_{\max - I_{1}} - F_{\overset{\_}{v}}} \right)^{2} + \left( {F_{\min - I_{1}}\; - F_{\overset{\_}{v}}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}} = F_{I_{1}}}}} & (13)\end{matrix}$

On the basis of the above condition of not changing the fatigue load inthe thrust direction, the influence of wind wheel rotating direction ona drive chain torsional fatigue load also needs to be considered.According to influence rule of the drive chain torsional fatigue, thestatistic which has a great influence on the drive chain torsionalfatigue is the mean value of load amplitude. That is, the influence ofturbulence variation on a torsional fatigue load may be controlled bymeans of keeping the mean value of the drive chain torque amplitudeabout the same.

When the turbulence increases from I₁ to I₂, the corresponding drivechain torque variation amplitude changes from (T_(min-I) ₁ , T_(max-I) ₁) to (T_(min-I) ₂ , T_(max-I) ₂ ) due to impact of wind speeddistribution variation. The following equation (14) needs to besatisfied to keep the torsional fatigue about the same.

T _(I) ₁ =T _(max-I) ₁ −T _(min-I) ₁ =T _(max-I) ₂ −T _(min-I) ₂ =T _(I)₂   (14)

According to an original design, the maximum torque is T_(max-I) ₁=T_(r), where T_(r) is rated torque. Similar to the foregoing analysison thrust, the wind wheel rotating speed may fall into region II orregion I in FIG. 4 due to impact of wind speed range. When the windwheel rotating speed is in region I, the rotating speed isω_(low)=ω_(min). When the rotating speed is in region II, the wind powergenerator set is running in a state with optimum tip speed ratio, andthe rotating speed is calculated according to formula (8). The torque Tis calculated according to formula (15), where C_(p) is wind energyutilization factor.

$\begin{matrix}{T = \frac{\pi \; \rho \; R^{5}C_{p}\omega^{2}}{2\lambda^{3}G^{3}}} & (15)\end{matrix}$

The maximum torque permitted when the turbulence intensity increases toI₂ is calculated according to formulas (14) and (16).

T _(max-I) ₂ =T _(max-I) ₁ −T _(min-I) ₁ +T _(min-I) ₂   (16)

From the above, in embodiments of the present disclosure, the step ofadjusting a maximum rotating speed and a maximum torque of the windwheel in the wind speed distribution range according to the thrustvariation amplitude includes:

adjusting a maximum rotating speed ω_(high) of the wind power generatorset in the wind speed distribution range according to

$\begin{matrix}{F_{I_{2}} = {\frac{\sqrt{\frac{\left( {\left( {F_{\max - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2} + \left( {F_{\min - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}^{\prime}} = {\frac{\sqrt{\frac{\left( {\left( {F_{\max - I_{1}} - F_{\overset{\_}{v}}} \right)^{2} + \left( {F_{\min - I_{1}} - F_{\overset{\_}{v}}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}} = F_{I_{1}}}}} & (13)\end{matrix}$

when the turbulence intensity increases from I₁ to I₂ and the thrustvariation amplitude changes from (F_(min-I) ₁ , F_(max-I) ₁ ) to(F_(min-I) ₂ , F_(max-I) ₂ ) due to variation of the wind speed; and

adjusting a maximum torque T_(max-I) ₂ =T_(max-I) ₁ −T_(min-I) ₁+T_(min-I) ₂ of the wind power generator set in the wind speeddistribution range according to T_(I) ₁ =T_(max-I) ₁ −T_(min-I) ₁=T_(max-I) ₂ −T_(min-I) ₂ =T_(I) ₂ when the turbulence intensityincreases from I₁ to I₂ and the torque variation amplitude of the windpower generator set changes from (T_(min-I) ₁ , T_(max-I) ₁ ) to(T_(min-I) ₂ , T_(max-I) ₂ ) due to variation of the wind speed,

where F′ _(v) is thrust corresponding to the maximum rotating speed.

It is important to note that, in embodiments of the present disclosure,when the rotating speed and torque are adjusted according to the methodabove, restrictions on matching the rotating speed with the torque of apower generation system also need to be considered. The output maximumtorque is restricted according to temperature rise relationship of thepower generation system, and the limit value is relevant tocharacteristics of the power generation system. As shown in FIG. 5, themaximum torque is restricted according to a power generation systemcharacteristic curve of the wind power generator set.

In the technical solutions in embodiments of the present disclosure, theturbulent wind speed distribution range is determined based on influenceof turbulence intensity on wind speed distribution and by means of astatistic method of great possibility events in the probability theory,then the force variation intensity of a wind power generator set in adirection perpendicular to wind wheel plane is defined in combinationwith definition of the turbulence intensity, and finally a solution tocontrol the rotating speed and torque to satisfy a standard fatigue loadis obtained according to a calculation principle of the fatigue load.With the above technical solutions, influence of over-standardturbulence intensity on a fatigue load of a wind power generator set maybe eliminated, and a loss of electric energy production brought by afatigue load caused by decreasing the over-standard turbulence may bereduced.

FIG. 7 is a structure schematic diagram illustrating a control apparatusof a wind power generator set provided in the present disclosure.

Referring to FIG. 7, the control apparatus of a wind power generator setincludes an acquisition module 1, a determining module 2, and anadjusting module 3.

The acquisition module 1 is configured to acquire a wind speed at alocation of the wind power generator set, calculate turbulence intensityaccording to the wind speed, and determine a wind speed distributionrange corresponding to the turbulence intensity.

The determining module 2 is configured to determine a thrust variationamplitude of the thrust in the wind speed distribution range based on arelationship among the thrust suffered by a wind wheel of the wind powergenerator set, a thrust coefficient and the wind speed.

The adjusting module 3 is configured to adjust a maximum rotating speedand a maximum torque of the wind wheel in the wind speed distributionrange according to the thrust variation amplitude. The maximum rotatingspeed and the maximum torque makes a fatigue load of the wind powergenerator set in the wind speed distribution range meet a presetstandard.

Preferably, the acquisition module 1 includes an acquisition module, acalculation unit, and a first determining unit.

The acquisition module is configured to acquire a wind speed at thelocation of the wind power generator set in a preset period, andcalculate an average wind speed v in the preset period.

The calculation unit is configured to calculate turbulence intensity

$I = {\frac{\delta}{\overset{\_}{v}} = \frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}}{\overset{\_}{v}}}$

according to the average wind speed v, and determine a Gaussiandistribution

${{f(v)} = {\frac{1}{\delta \sqrt{2\pi}}e^{- \frac{{({v - \overset{\_}{v}})}^{2}}{2\delta^{2}}}}},$

with a center of v and a standard deviation of

${\delta = \sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}},$

of a wind speed distribution range corresponding to the turbulenceintensity according to the turbulence intensity

$I = {\frac{\delta}{\overset{\_}{v}} = {\frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}}{\overset{\_}{v}}.}}$

The first determining unit is configured to determine the wind speeddistribution range (v−1.96δ, v+196δ) according to the theory of smallprobability event and the Gaussian distribution

${f(v)} = {\frac{1}{\delta \sqrt{2\pi}}{e^{- \frac{{({v - \overset{\_}{v}})}^{2}}{2\; \delta^{2}}}.}}$

In the above, I denotes the turbulence intensity corresponding to theaverage wind speed v, v_(i) denotes an instantaneous wind speed of thei-th sampling point, and N denotes the number of sampling points in thepreset period.

Preferably, the determining module 2 includes a second determining unit,a third determining unit, and a fourth determining unit.

The second determining unit is configured to determine a relation

$F = {\frac{1}{2}\rho \; {Av}^{2}{C_{t}\left( {\beta,\frac{\omega \; R}{v}} \right)}}$

among the thrust, a pitch angle β of a blade of a wind wheel and a windwheel rotating speed ω according to a relation F=1/2ρAv²C_(t)(β, λ)among the thrust suffered by the wind wheel of the wind power generatorset, the thrust coefficient and the wind speed and according to a tipspeed ratio

$\lambda = \frac{\omega \; R}{v}$

of the wind wheel.

The third determining unit is configured to determine a minimum thrust

$F_{\min - I} = {\frac{1}{2}\rho \; {{Av}_{\min}}^{2}{C_{t}\left( {\beta_{opt},\frac{\omega_{low}R}{v_{\min}}} \right)}}$

corresponding to a minimum wind speed v_(min)=v−1.96δ in the wind speeddistribution range and a maximum thrust

$F_{\max - I} = {\frac{1}{2}\rho \; {{Av}_{\max}}^{2}{C_{t}\left( {\beta_{opt},\frac{\omega_{high}R}{v_{\max}}} \right)}}$

corresponding to a maximum wind speed v_(max)=v−1.96δ in the wind speeddistribution range according to the formula

$F = {\frac{1}{2}\rho \; {Av}^{2}{{C_{t}\left( {\beta,\frac{\omega \; R}{v}} \right)}.}}$

The fourth determining unit is configured to determine a thrustvariation amplitude

$F_{I} = \frac{\sqrt{\frac{\left( {\left( {F_{\max - I} - F_{\overset{\_}{v}}} \right)^{2} + \left( {F_{\min - I} - F_{\overset{\_}{v}}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}}$

of the thrust in the wind speed distribution range according to theminimum thrust, the maximum thrust and a relation between the thrust andthe wind speed

$F = {\frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\; \left( {F_{v_{i}} - F_{\overset{\_}{v}}} \right)^{2}}}}{F_{\overset{\_}{v}}}.}$

In the above, ρ is an air density, A is a wind wheel swept area, v is awind speed, C_(t)(β, λ) is the thrust coefficient relevant to the pitchangle β of the blade of the wind wheel and the tip speed ratio λ, R is awind wheel radius, ω_(min) is a minimum rotating speed of the wind powergenerator set in grid connection, ω_(low) is a minimum rotating speed ofthe wind power generator set, ω_(high) is a maximum rotating speed ofthe wind power generator set, β_(opt) is an optimum pitch angle, F _(v)is thrust suffered at the average wind speed v, F_(I) is a thrustvariation amplitude during the preset time at the average wind speed vand at the turbulence intensity I, and F_(v) _(i) is thrust suffered bythe wind wheel at the i-th sampling point with an instantaneous windspeed of v_(i).

Preferably, the adjusting module 3 includes a rotating speed adjustingunit and a torque adjusting unit.

The rotating speed adjusting unit is configured to adjust a maximumrotating speed ω_(high) of the wind power generator set in the windspeed distribution range according to

$F_{I_{2}} = {\frac{\sqrt{\frac{\left( {\left( {F_{\max - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2} + \left( {F_{\min - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}^{\prime}} = {\frac{\sqrt{\frac{\left( {\left( {F_{\max - I_{1}} - F_{\overset{\_}{v}}} \right)^{2} + \left( {F_{\min - I_{1}} - F_{\overset{\_}{v}}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}} = F_{I_{1}}}}$

when the turbulence intensity increases from I₁ to I₂ and the thrustvariation amplitude changes from (F_(min-I) ₁ , F_(max-I) ₁ ) to(F_(min-I) ₂ , F_(max-I) ₂ ) due to variation of the wind speed.

The torque adjusting unit is configured to adjust a maximum torqueT_(max-I) ₂ =T_(max-I) ₁ −T_(min-I) ₁ +T_(min-I) ₂ of the wind powergenerator set in the wind speed distribution range according to T_(I) ₁=T_(max-I) ₁ −T_(min-I) ₁ =T_(max-I) ₂ −T_(min-I) ₂ =T_(I) ₂ when theturbulence intensity increases from I₁ to I₂ and the torque variationamplitude of the wind power generator set changes from (T_(min-I) ₁ ,T_(max-I) ₁ ) to (T_(min-I) ₂ , T_(max-I) ₂ ) due to variation of thewind speed.

In the above, F′ _(v) is thrust corresponding to the maximum rotatingspeed.

Preferably, the control apparatus provided in embodiments of the presentdisclosure further includes a restricting module.

The restricting module is configured to restrict the maximum torqueaccording to a power generation system characteristic curve of the windpower generator set.

It is important to note that, the control apparatus of a wind powergenerator set provided in the embodiments can adopt the control methodof a wind power generator set in the foregoing method embodiments torealize all technical solutions in the above method embodiments.Functions of each module may be achieved specifically according tomethods in the foregoing method embodiments. For the details ofprocesses, reference may be made to relevant descriptions in the aboveembodiments, which will not be repeated herein.

It is apparent from the above technical solutions that, with the controlmethod and the control apparatus of a wind power generator set providedin the present disclosure, a wind speed at a location of the wind powergenerator set is acquired, turbulence intensity is calculated accordingto the wind speed, and a wind speed distribution range corresponding tothe turbulence intensity is determined; a thrust variation amplitude ofthe thrust in the wind speed distribution range is determined based on arelationship among the thrust suffered by a wind wheel of the wind powergenerator set, a thrust coefficient and the wind speed; and a maximumrotating speed and a maximum torque of the wind wheel in the wind speeddistribution range are adjusted according to the thrust variationamplitude, where the maximum rotating speed and the maximum torque makesa fatigue load of the wind power generator set in the wind speeddistribution range meet a preset standard. With the technical solutionsprovided in the present disclosure, a wind speed distribution range isdetermined according to actual measured turbulence intensity, and then amaximum rotating speed and a maximum torque are adjusted according tothe wind speed distribution range. When the turbulence intensity isbeyond a specified level, a fatigue load of a wind power generator setin the wind speed distribution range is made to meet a preset standardby adjusting the maximum rotating speed and the maximum torque, insteadof shutting down the wind power generator set. Thereby influence on thewind power generator set is reduced when the turbulence intensity isbeyond the specified level and a loss of generated electric energy islowered.

For illustrating the technical solutions provided in the presentdisclosure being applied to a wind power generator set, taking a 2MWwind power generator set as an example, fatigue loads, which areadjusted and controlled by means of the above methods, are calculatedrespectively under conditions of exceeding 20%, 40%, and 60% of A-classturbulence according to the standard A-class turbulence intensity in theGL specifications.

The following tables illustrate a ratio of a fatigue load at a keycoordinate point of a wind power generator set to a standard A-classturbulence design value, in the condition of a ratio of adjustedrotating speed to rated rotating speed ω_(r) and a ratio of adjustedtorque to rated torque T_(r) calculated by means of the foregoingmethods for different over-standard turbulence intensity. As shown inTable 1-11, by applying the methods to adjust a controlling statesynthetically according to turbulence intensity variation, a fatigueload at a key coordinate point of a wind power generator set is at most3% over a standard design value, which hardly affects security andservice life of the wind power generator set.

TABLE 1 Blade Root Mx Fatigue Load Comparison M = 4 M = 7 M = 10 Bladeroot 1 Mx [Nm] Ratio Standard A-class turbulence design fatigue 1 1 1load Exceeding 20% of A-class turbulence, 0.972 0.983 0.987 rotatingspeed is 0.9 ω_(r) and torque is 0.93 T_(r) Exceeding 40% of A-classturbulence, 0.908 0.938 0.951 rotating speed is 0.74 ω_(r) and torque is0.81 T_(r) Exceeding 60% of A-class turbulence, 0.887 0.927 0.945rotating speed is 0.68 ω_(r) and torque is 0.72 T_(r)

TABLE 2 Blade Root My Fatigue Load Comparison M = 4 M = 7 M = 10 Bladeroot 1 My [Nm] Ratio Standard A-class turbulence 1 1 1 design fatigueload Exceeding 20% of A-class turbulence, 0.954 0.926 0.891 rotatingspeed is 0.9 ω_(r) and torque is 0.93 T_(r) Exceeding 40% of A-classturbulence, 0.858 0.879 0.864 rotating speed is 0.74 ω_(r) and torque is0.81 T_(r) Exceeding 60% of A-class turbulence, 0.905 0.971 0.99rotating speed is 0.68 ω_(r) and torque is 0.72 T_(r)

TABLE 3 Blade Root Mz Fatigue Load Comparison M = 4 M = 7 M = 10 Bladeroot 1 Mz [Nm] Ratio Standard A-class turbulence 1 1 1 design fatigueload Exceeding 20% of A-class turbulence, 0.825 0.842 0.852 rotatingspeed is 0.9 ω_(r) and torque is 0.93 T_(r) Exceeding 40% of A-classturbulence, 0.578 0.646 0.694 rotating speed is 0.74 ω_(r) and torque is0.81 T_(r) Exceeding 60% of A-class turbulence, 0.535 0.623 0.679rotating speed is 0.68 ω_(r) and torque is 0.72 T_(r)

TABLE 4 Rotating Hub Coordinate System Mx Fatigue Load Comparison M = 4M = 7 M = 10 Rotating hub Mx [Nm] Ratio Standard A-class turbulence 1 11 design fatigue load Exceeding 20% of A-class turbulence, 0.981 0.9580.941 rotating speed is 0.9 ω_(r) and torque is 0.93 T_(r) Exceeding 40%of A-class turbulence, 0.967 0.942 0.931 rotating speed is 0.74 ω_(r)and torque is 0.81 T_(r) Exceeding 60% of A-class turbulence, 1.0190.925 0.89 rotating speed is 0.68 ω_(r) and torque is 0.72 T_(r)

TABLE 5 Rotating Hub Coordinate System My Fatigue Load Comparison M = 4M = 7 M = 10 Rotating hub My [Nm] Ratio Standard A-class turbulence 1 11 design fatigue load Exceeding 20% of A-class turbulence, 0.974 1.0161.052 rotating speed is 0.9 ω_(r) and torque is 0.93 T_(r) Exceeding 40%of A-class turbulence, 0.832 0.881 0.916 rotating speed is 0.74 ω_(r)and torque is 0.81 T_(r) Exceeding 60% of A-class turbulence, 0.85 0.8940.924 rotating speed is 0.68 ω_(r) and torque is 0.72 T_(r)

TABLE 6 Rotating Hub Coordinate System Mz Fatigue Load Comparison M = 4M = 7 M = 10 Rotating hub Mz [Nm] Ratio Standard A-class turbulence 1 11 design fatigue load Exceeding 20% of A-class turbulence, 0.996 1.0391.072 rotating speed is 0.9 ω_(r) and torque is 0.93 T_(r) Exceeding 40%of A-class turbulence, 0.833 0.895 0.938 rotating speed is 0.74 ω_(r)and torque is 0.81 T_(r) Exceeding 60% of A-class turbulence, 0.8720.927 0.959 rotating speed is 0.68 ω_(r) and torque is 0.72 T_(r)

TABLE 7 Stationary Hub Coordinate System Mx Fatigue Load Comparison M =4 M = 7 M = 10 Stationary hub Mx [MNm] Ratio Standard A-class turbulence1 1 1 design fatigue load Exceeding 20% of A-class turbulence, 0.9810.958 0.941 rotating speed is 0.9 ω_(r) and torque is 0.93 T_(r)Exceeding 40% of A-class turbulence, 0.967 0.942 0.931 rotating speed is0.74 ω_(r) and torque is 0.81 T_(r) Exceeding 60% of A-class turbulence,1.019 0.925 0.89 rotating speed is 0.68 ω_(r) and torque is 0.72 T_(r)

TABLE 8 Stationary Hub Coordinate System My Fatigue Load Comparison M =4 M = 7 M = 10 Stationary hub My [MNm] Ratio Standard A-class turbulence1 1 1 design fatigue load Exceeding 20% of A-class turbulence, 0.9890.999 0.996 rotating speed is 0.9 ω_(r) and torque is 0.93 T_(r)Exceeding 40% of A-class turbulence, 0.873 0.879 0.87 rotating speed is0.74 ω_(r) and torque is 0.81 T_(r) Exceeding 60% of A-class turbulence,0.937 0.953 0.95 rotating speed is 0.68 ω_(r) and torque is 0.72 T_(r)

TABLE 9 Stationary Hub Coordinate System Mz Fatigue Load Comparison M =4 M = 7 M = 10 Stationary hub Mz [MNm] Ratio Standard A-class turbulence1 1 1 design fatigue load Exceeding 20% of A-class turbulence, 1.0011.036 1.048 rotating speed is 0.9 ω_(r) and torque is 0.93 T_(r)Exceeding 40% of A-class turbulence, 0.908 0.941 0.96 rotating speed is0.74 ω_(r) and torque is 0.81 T_(r) Exceeding 60% of A-class turbulence,1.016 1.069 1.097 rotating speed is 0.68 ω_(r) and torque is 0.72 T_(r)

TABLE 10 Tower Footing My Fatigue Load Comparison Tower My, M = 4 M = 7M = 10 Tower station height = 1.14 m [MNm] Ratio Standard A-classturbulence 1 1 1 design fatigue load Exceeding 20% of A-classturbulence, 0.83 0.799 0.78 rotating speed is 0.9 ω_(r) and torque is0.93 T_(r) Exceeding 40% of A-class turbulence, 0.815 0.774 0.763rotating speed is 0.74 ω_(r) and torque is 0.81 T_(r) Exceeding 60% ofA-class turbulence, 1.031 0.975 0.976 rotating speed is 0.68 ω_(r) andtorque is 0.72 T_(r)

TABLE 11 Tower Footing Mz Fatigue Load Comparison Tower Mz, M = 4 M = 7M = 10 Tower station height = 1.14 m [MNm] Ratio Standard A-classturbulence 1 1 1 design fatigue load Exceeding 20% of A-classturbulence, 0.982 1.024 1.042 rotating speed is 0.9 ω_(r) and torque is0.93 T_(r) Exceeding 40% of A-class turbulence, 0.896 0.932 0.955rotating speed is 0.74 ω_(r) and torque is 0.81 T_(r) Exceeding 60% ofA-class turbulence, 1.004 1.064 1.094 rotating speed is 0.68 ω_(r) andtorque is 0.72 T_(r)

From the foregoing Table 1-11, it is apparent that, by applyingtechnical solutions in the present disclosure, a fatigue load on a keyor important component of a wind power generator set may satisfystandard design requirements under different degrees of over-standardturbulence intensity, and the power outputted by the wind powergenerator set may be maximized based on synthesizing all aspects of thefatigue load.

For the convenience of description, the system is described as unitswith various functions. Apparently, the functions of the units may berealized in a same or multiple software and/or hardware.

The embodiments of the disclosure are described in a progressive way,and each embodiment emphasizes the differences from other embodiments,and the same or similar contents of the embodiments may be referred toeach other. Since the system disclosed by the embodiments corresponds tothe method disclosed by the embodiments, the description of the systemis brief, and for relevant matters references may be made to thedescription of the method. The description of apparatus and embodimentsare merely exemplary. The units described as separate parts may or maynot be physically separate, and parts displayed as units may or may notbe physical units, may be located in one position, or may be distributedon multiple network units. Some or all of the units may be selectedaccording to actual needs to achieve the objectives of the solutions inthe embodiments. A person of ordinary skill in the art may understandand implement the embodiments of the present invention without creativeefforts.

A person of ordinary skill in the art may be aware that, in combinationwith the examples described in the embodiments disclosed in thisspecification, method steps and units may be implemented by electronichardware, computer software, or a combination thereof. To clearlydescribe the interchangeability between the hardware and the software,the foregoing has generally described steps and compositions of eachembodiment according to functions. Whether the functions are performedby hardware or software depends on particular applications and designconstraint conditions of the technical solutions. A person of ordinaryskill in the art may use different methods to implement the describedfunctions for each particular application, but it should not beconsidered that the implementation goes beyond the scope of the presentinvention.

Steps of the method or algorithm described in conjunction with theembodiments disclosed herein may be implemented directly with hardware,a software module executed by a processor, or a combination thereof. Thesoftware module may be placed in a Random Access Memory (RAM), a memory,a Read Only Memory (ROM), an electrically-programmable ROM, anelectrically erasable programmable ROM, a register, a hard disk, aremovable disk, a CD-ROM, or a storage medium in any other forms wellknown in the art.

The above description of the embodiments enables those skilled in theart to implement or use the present disclosure. Various modifications tothese embodiments are apparent to those skilled in the art, and thegeneral principle defined herein may be implemented in other embodimentswithout deviating from the spirit or scope of the present disclosure.Therefore, the present disclosure is not limited to these embodimentsdescribed herein, but in accordance with the widest scope consistentwith the principle and novel features disclosed herein.

1. A control method of a wind power generator set, comprising: acquiringa wind speed at a location of the wind power generator set, calculatingturbulence intensity according to the wind speed, and determining a windspeed distribution range corresponding to the turbulence intensity;determining a thrust variation amplitude of thrust in the wind speeddistribution range based on a relationship among the thrust suffered bya wind wheel of the wind power generator set, a thrust coefficient andthe wind speed; and adjusting a maximum rotating speed and a maximumtorque of the wind wheel in the wind speed distribution range accordingto the thrust variation amplitude, wherein the maximum rotating speedand the maximum torque makes a fatigue load of the wind power generatorset in the wind speed distribution range meet a preset standard.
 2. Thecontrol method according to claim 1, wherein the step of acquiring awind speed at a location of the wind power generator set, calculatingturbulence intensity according to the wind speed, and determining a windspeed distribution range corresponding to the turbulence intensitycomprises: acquiring a wind speed at the location of the wind powergenerator set in a preset period, and calculating an average wind speedv in the preset period; calculating the turbulence intensity$I = {\frac{\delta}{\overset{\_}{v}} = \frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}}{\overset{\_}{v}}}$according to the average wind speed v , and determining a Gaussiandistribution${{f(v)} = {\frac{1}{\delta \sqrt{2\; \pi}}e^{- \frac{{({v - \overset{\_}{v}})}^{2}}{2\; \delta^{2}}}}},$with a center of v and a standard deviation of${\delta = \sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}},$of a wind speed distribution range corresponding to the turbulenceintensity according to the turbulence intensity${I = {\frac{\delta}{\overset{\_}{v}} = \frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}}{\overset{\_}{v}}}};$and determining the wind speed distribution range (v−1.96δ, v+196δ)according to the theory of small probability event and the Gaussiandistribution${{f(v)} = {\frac{1}{\delta \sqrt{2\; \pi}}e^{- \frac{{({v - \overset{\_}{v}})}^{2}}{2\; \delta^{2}}}}},$where I denotes the turbulence intensity corresponding to the averagewind speed v, v_(i) denotes an instantaneous wind speed of the i-thsampling point, and N denotes the number of sampling points in thepreset period.
 3. The control method according to claim 2, wherein thestep of determining a thrust variation amplitude of the thrust in thewind speed distribution range based on a relationship among the thrustsuffered by a wind wheel of the wind power generator set, a thrustcoefficient and the wind speed comprises: determining a relation$F = {\frac{1}{2}\rho \; {Av}^{2}{C_{t}\left( {\beta,\frac{\omega \; R}{v}} \right)}}$among the thrust, a pitch angle β of a blade of the wind wheel and awind wheel rotating speed ω according to a relation F=1/2ρAv²C_(t)(β, λ)among the thrust suffered by the wind wheel of the wind power generatorset, the thrust coefficient and the wind speed and according to a tipspeed ratio $\lambda = \frac{\omega \; R}{v}$ of the wind wheel;determining a minimum thrust$F_{\min - I} = {\frac{1}{2}\rho \; {Av}_{\min}^{2}{C_{t}\left( {\beta_{opt},\frac{\omega_{low}\; R}{v_{\min}}} \right)}}$corresponding to a minimum wind speed v_(min)=v1.96δ in the wind speeddistribution range and a maximum thrust$F_{\max - I} = {\frac{1}{2}\rho \; {Av}_{\max}^{2}{C_{t}\left( {\beta_{opt},\frac{\omega_{high}\; R}{v_{\max}}} \right)}}$corresponding to a maximum wind speed v_(max)=v+1.96δ in the wind speeddistribution range according to the formula${F = {\frac{1}{2}\rho \; {Av}^{2}{C_{t}\left( {\beta,\frac{\omega \; R}{v}} \right)}}};$and determining a thrust variation amplitude$F_{I} = \frac{\sqrt{\frac{\left( {\left( {F_{\max - I} - F_{\overset{\_}{v}}} \right)^{2} + \left( {F_{\min - I} - F_{\overset{\_}{v}}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}}$of the thrust in the wind speed distribution range according to theminimum thrust, the maximum thrust and a relation between the thrust andthe wind speed${F = \frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {F_{v_{i}} - F_{\overset{\_}{v}}} \right)^{2}}}}{F_{\overset{\_}{v}}}},$where ρ is an air density, A is a wind wheel swept area, v is a windspeed, C_(t)(β, λ) is the thrust coefficient relevant to the pitch angleβ of the blade of the wind wheel and the tip speed ratio λ, R is a windwheel radius, ω_(min) is a minimum rotating speed of the wind powergenerator set in grid connection, ω_(low) is a minimum rotating speed ofthe wind power generator set, ω_(high) is a maximum rotating speed ofthe wind power generator set, β_(opt) is an optimum pitch angle, F _(v), is thrust suffered at the average wind speed v, F_(I) is a thrustvariation amplitude during the preset time at the average wind speed vand at the turbulence intensity I, and F_(v) _(i) is thrust suffered bythe wind wheel at the i-th sampling point with an instantaneous windspeed of v_(i).
 4. The control method according to claim 3, wherein thestep of adjusting a maximum rotating speed and a maximum torque of thewind wheel in the wind speed distribution range according to the thrustvariation amplitude comprises: adjusting the maximum rotating speedω_(high) of the wind power generator set in the wind speed distributionrange according to$F_{I_{2}} = {\frac{\sqrt{\frac{\left( {\left( {F_{\max - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2} + \left( {F_{\min - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}^{\prime}} = {\frac{\sqrt{\frac{\left( {\left( {F_{\max - I_{1}} - F_{\overset{\_}{v}}} \right)^{2} + \left( {F_{\min - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}} = F_{I_{1}}}}$when the turbulence intensity increases from I₁ to I₂ and the thrustvariation amplitude changes from (F_(min-I) ₁ , F_(max-I) ₁ ) to(F_(min-I) ₂ , F_(max-I) ₂ ) due to variation of the wind speed; andadjusting a maximum torque T_(max-I) ₂ =T_(max-I) ₁ −T_(min-I) ₁+T_(min-I) ₂ of the wind power generator set in the wind speeddistribution range according to T_(I) ₁ =T_(max-I) ₁ −T_(min-I) ₁=T_(max-I) ₂ −T_(min-I) ₂ =T_(I) ₂ when the turbulence intensityincreases from I₁ to I₂ and the torque variation amplitude T_(r) of thewind power generator set changes from (T_(min-I) ₁ , T_(max-I) ₁ ) to(T_(min-I) ₂ , T_(max-I) ₂ ) due to variation of the wind speed, whereF′ _(v) is thrust corresponding to the maximum rotating speed.
 5. Thecontrol method according to claim 1, further comprising: restricting themaximum torque according to a power generation system characteristiccurve of the wind power generator set.
 6. A control apparatus of a windpower generator set, comprising: an acquisition module, configured toacquire a wind speed at a location of the wind power generator set,calculate turbulence intensity according to the wind speed, anddetermine a wind speed distribution range corresponding to theturbulence intensity; a determining module, configured to determine athrust variation amplitude of the thrust in the wind speed distributionrange based on a relationship among the thrust suffered by a wind wheelof the wind power generator set, a thrust coefficient and the windspeed; and an adjusting module, configured to adjust a maximum rotatingspeed and a maximum torque of the wind wheel in the wind speeddistribution range according to the thrust variation amplitude, whereinthe maximum rotating speed and the maximum torque makes a fatigue loadof the wind power generator set in the wind speed distribution rangemeet a preset standard.
 7. The control apparatus according to claim 6,wherein the acquisition unit comprises: an acquisition module,configured to acquire a wind speed at the location of the wind powergenerator set in a preset period, and calculating an average wind speedv in the preset period; a calculation unit, configured to calculate theturbulence intensity$I = {\frac{\delta}{\overset{\_}{v}} = \frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}}{\overset{\_}{v}}}$according to the average wind speed v , and determine a Gaussiandistribution${{f(v)} = {\frac{1}{\delta \sqrt{2\pi}}e^{- \frac{{({v - \overset{\_}{v}})}^{2}}{2\delta^{2}}}}},$with a center of v and a standard deviation of${\delta = \sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}},$of a wind speed distribution range corresponding to the turbulenceintensity according to the turbulence intensity${I = {\frac{\delta}{\overset{\_}{v}} = \frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {v_{i} - \overset{\_}{v}} \right)^{2}}}}{\overset{\_}{v}}}};$and a first determining unit, configured to determine the wind speeddistribution range (v−1.96δ, v+196δ) according to the theory of smallprobability event and the Gaussian distribution${{f(v)} = {\frac{1}{\delta \sqrt{2\pi}}e^{- \frac{{({v - \overset{\_}{v}})}^{2}}{2\delta^{2}}}}},$where I denotes the turbulence intensity corresponding to the averagewind speed v, v_(i) denotes an instantaneous wind speed of the i-thsampling point, and N denotes the number of sampling points in thepreset period.
 8. The control apparatus according to claim 7, whereinthe determining module comprises: a second determining unit, configuredto determine a relation$F = {\frac{1}{2}\rho \; {Av}^{2}{C_{t}\left( {\beta,\frac{\omega \; R}{v}} \right)}}$among the thrust, a pitch angle β of a blade of a wind wheel and a windwheel rotating speed ω according to a relation F=1/2ρAv²C_(t)(β, λ)among the thrust suffered by the wind wheel of the wind power generatorset, the thrust coefficient and the wind speed and according to a tipspeed ratio $\lambda = \frac{\omega \; R}{v}$ of the wind wheel; athird determining unit, configured to determine a minimum thrust$F_{\min - I} = {\frac{1}{2}\rho \; {Av}_{\min}^{2}{C_{t}\left( {\beta_{opt},\frac{\omega_{low}R}{v_{\min}}} \right)}}$corresponding to a minimum wind speed v_(min)=v−1.96δ in the wind speeddistribution range and a maximum thrust$F_{\max - I} = {\frac{1}{2}\rho \; {Av}_{\max}^{2}{C_{t\;}\left( {\beta_{opt},\frac{\omega_{high}R}{v_{\max}}} \right)}}$corresponding to a maximum wind speed v_(max)=v+1.96δ in the wind speeddistribution range according to the formula${F = {\frac{1}{2}\rho \; {Av}^{2}{C_{t}\left( {\beta,\frac{\omega \; R}{v}} \right)}}};$and a fourth determining unit, configured to determine a thrustvariation amplitude$F_{I} = \frac{\sqrt{\frac{\left( {\left( {F_{\max - I} - F_{\overset{\_}{v}}} \right)^{2} + \left( {F_{\min - I} - F_{\overset{\_}{v}}^{\prime}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}}$of the thrust in the wind speed distribution range according to theminimum thrust, the maximum thrust and a relation between the thrust andthe wind speed${F = \frac{\sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {F_{v_{i}} - F_{\overset{\_}{v}}} \right)^{2}}}}{F_{\overset{\_}{v}}}},$where ρ is an air density, A is a wind wheel swept area, v is a windspeed, C_(t)(β, λ) is the thrust coefficient relevant to the pitch angleβ of the blade of the wind wheel and the tip speed ratio λ, R is a windwheel radius, ω_(min) is a minimum rotating speed of the wind powergenerator set in grid connection, ω_(low) is a minimum rotating speed ofthe wind power generator set, ω_(high) is a maximum rotating speed ofthe wind power generator set, β_(opt) is an optimum pitch angle, F_(v)_(i) is thrust suffered at the average wind speed v, F_(I) is a thrustvariation amplitude during the preset time at the average wind speed vand at the turbulence intensity I, and F_(v) _(i) is thrust suffered bythe wind wheel at the i-th sampling point with an instantaneous windspeed of v_(i).
 9. The control apparatus according to claim 8, whereinthe adjusting module comprises: a rotating speed adjusting unit,configured to adjust a maximum rotating speed ω_(high) of the wind powergenerator set in the wind speed distribution range according to$F_{I_{2}} = {\frac{\sqrt{\frac{\left( {\left( {F_{\max - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2} + \left( {F_{\min - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}^{\prime}} = {\frac{\sqrt{\frac{\left( {\left( {F_{\max - I_{1}} - F_{\overset{\_}{v}}} \right)^{2} + \left( {F_{\min - I_{2}} - F_{\overset{\_}{v}}^{\prime}} \right)^{2}} \right)}{2}}}{F_{\overset{\_}{v}}} = F_{I_{1}}}}$when the turbulence intensity increases from I₁ to I₂ and the thrustvariation amplitude changes from (F_(min-I) ₁ , F_(max-I) ₁ ) to(F_(min-I) ₂ , F_(max-I) ₂ ) due to variation of the wind speed; and atorque adjusting unit, configured to adjust a maximum torque T_(max-I) ₂=T_(max-I) ₁ −T_(min-I) ₁ +T_(min-I) ₂ of the wind power generator setin the wind speed distribution range according to T_(I) ₁ =T_(max-I) ₁−T_(min-I) ₁ =T_(max-I) ₂ −T_(min-I) ₂ =T_(I) ₂ when the turbulenceintensity increases from I₁ to I₂ and the torque variation amplitude ofthe wind power generator set changes from (T_(min-I) ₁ , T_(max-I) ₁ )to (T_(min-I) ₂ , T_(max-I) ₂ ) due to variation of the wind speed,where F′ _(v) is thrust corresponding to the maximum rotating speed. 10.The control apparatus according to claim 6, wherein the apparatusfurther comprises: a restricting module, configured to restrict themaximum torque according to a power generation system characteristiccurve of the wind power generator set.